1. Field of the Invention
The present invention relates to abnormal discharge detection devices and abnormal discharge detection methods, and more particularly to devices and methods for detecting an abnormal fluid discharge operation in a fluid supply device using a piezoelectric element.
2. Description of the Related Art
Pumps using a piezoelectric element as an actuator are known in the art. Such pumps are also called diaphragm pumps. Since these pumps can discharge a very small amount of fluid, these pumps are used for fluid supply devices that are required to supply fluid with reduced frequency.
For example, Japanese Patent Application Publication No. 2004-108388 (JP 2004-108388 A) and Japanese Patent Application Publication No. 2012-102803 (JP 2012-102803 A) disclose a fluid supply device using such a pump, specifically an oil supply device (oil supply unit) integral with a rolling bearing.
If there is an abnormality in the pump mounted on the fluid supply device, fluid may not be discharged from the pump. In particular, in the case where the fluid supply device is an oil supply unit mounted integrally with a rolling bearing, an abnormality may occur in the pump due to vibration etc., which may result in poor lubrication of the rolling bearing.